Jar opening fixture

ABSTRACT

A fixture for use in loosening and removing the lid from a vacuum sealed, screw-type, bottle or jar including a base member which is adapted to be rigidly connected to a supporting surface. The base member supports first and second gripping members, the former being stationary and the latter being mounted for linear movement under control of an actuating rod connected thereto. A locking device is provided for controlling the movement of the actuating rod, the locking device permitting unlimited linear movement of the actuating rod in a direction to bring the gripping members together and releasably inhibiting movement of the actuating rod in an opposite direction whereby the second gripping member may be moved toward the first gripping member to secure the lid therebetween and the locking device will hold the second gripping member in position, such gripping member, in turn, holding the lid, until released. The second gripping member includes a serrated surface which is pivotably mounted on the base member in such a manner that rotation of the lid tends to rotate such surface in a direction to tighten its hold on the lid to prevent slipping thereof.

United States Patent 1191 Graver 1 Apr. 3, 1973 [54] JAR OPENING FIXTURE [57] ABSTRACT Inventor: Richard 7926 La Casa A fixture for use in loosening and removing the lid y, Buena Park, Calif- 90620 from a vacuum sealed, screw-type, bottle or jarinclud- [22] Filed: Apr. 16, 1971 ing a base member which is adapted to be rigidly connected to a supporting surface. The base member sup- PP 134,577 ports first and second gripping members, the former being stationary and thelatter being mounted for 521 US. Cl. ..s1/3.3 R, 8l/3.42 linear movement under control of on actuating rod 51 Int. Cl. ..B67b 7/36 connected thereto A locking device is Provided for 581 Field of Search ..s1/3.3, 3.4, 3.42 n r l ng the movement of the c uating rod, the locking device permitting unlimited linear movement [56] References Cited of the actuating rod in a direction to bring the gripping members together and releasably inhibiting UNITED STATES PATENTS movement of the actuating rod in an opposite 1,394,033 10/1921 McLeod etal. ..s1/3;42 direction w y the Second pp g member y 2,000,962 5/1935 be moved toward the first gripping member to secure 3,293,957 12/1966 the lid therebetween and the locking device will hold 2,414,635 1947 the second gripping member in position, such gripping 3,163,060 12/1964 Loughry et al ..8l/3.3 member in turn the until released. The FOREIGN PATENTS OR APPLICATIONS second gripping member includes a serrated surface which is pivotably mounted on the base member in 84,237 3/1920 Switzerland ..8l/3.42

Primary Examiner-James L. Jones, Jr. Attorney-Philip M. Hinderstein such a manner that rotation of the lid tends to rotate such surface in a direction to tighten its hold on the lid to prevent slipping thereof.

} 12 Claims, 6 Drawing Figures PATENTEDAPR 3 197a 3.724, 296

sum 2 BF 2 INVENTOR.

R/CH/IRD r. GRAVE/Q ATTORNE Y5 JAR OPENING FIXTURE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jar opening fixture and more particularly, to a fixture which is operative to tightly grip the lid of a vacuum sealed, screw-type-bottle or jar to assist in the loosening and removal of such lid.

2. Description of the Prior Art It is well known that glass bottles and jars of the type in which food products and the like are sold are essentially always vacuum sealed with a metal lid.'While occasionally such lids are removable from the jar by prying them off, in most cases, the neck of the jar is externally threaded, the lid is internally threaded and the lid is removed from the jar by rotation thereof.

Because such glass jars are vacuumed sealed, it requires a large amount of torque to rotate the lid in order to loosen and remove it. As a result, women typically have a difficult time opening all of such vacuum sealed jars. However, the problem is not limited only to women. Especially in the case of small jars, where it is difficult to get a good grip on the lid, most men too have a difiicult time removing the lid.

It is therefore not uncommon to find people restoring to various methods for assistance in loosening and removing the lids of vacuum sealed jars. It is very common to run the lid under hot water to cause expansion thereof and then to tap the lid on a hard surface in'an attempt to loosen the lid. However, these methods are time consuming, annoying, and often incapable of providing the desired result.

Accordingly, many different types of mechanical devices have been suggested for assisting one in loosening and removing the lid of a vacuum sealed, screwtype jar. However, while there are many of such mechanical devices presently available, each has at least one significant disadvantage associated therewith. For example, some available mechanical devices simply do not grip the circumference of the lid with sufficient force to prevent slipping thereof. Other available mechanical devices are not capable of accepting the wide range of sizes that glass jars and lids come in.

One characteristic which is common to essentially all of the available mechanical devices for use in loosening and removing the lid of a screw-type jar is that they are of the hand held type. In other words, such mechanical devices are meant to be stored in a drawer until needed whereupon the device is, in some manner, attached to the lid of the jar to grip and loosen the same. As a result, it becomes necessary to hold the mechanical device in one hand and only the one remaining hand is available for holding the jar itself. However, most of such devices are simply awkward and difficult to use. Furthermore, there are many jars or bottles that come in sufficiently large sizes to make it difficult to hold the jar easily in one hand.

SUMMARY OF THE INVENTION In accordance with the present invention, these as well as other problems of the prior art are solved by providing a novel fixture which is operative to tightly grip the lid of a vacuum sealed, screw-type bottle or jar so as to assist in the opening-thereof. In the first instance, the design of the present fixture is such as to apply a substantial force to the 'lid as it is attempted to be rotated to insure that there is no slipping of such lid. Furthermore, the present fixture is capable of accepting a wide variety of sizes of jars and lids. Also, the present fixture is designed so as to be rigidly connected to a supporting surface, such as the bottom of a kitchen cabinet, where it will remain permanently mounted. Accordingly, it is not necessary to hold the present fixture in one hand and the jar in the other, but both hands are available for gripping the jar.

Briefly, the present fixture for use in loosening and removing the lid from a vacuum sealed, screw-type bottle or jar includes a base member which is adapted to be rigidly connected to a supporting surface, such as the underneath surface of a kitchen cabinet. The base member supports first and second gripping members, the former being stationary and the latter being mounted for linear movement under control of an actuating rod connected thereto. A locking device is provided for controlling the movement of the actuating rod, the locking device permitting unlimited linear movement of the actuating rod in a direction to bring the gripping members together and releasably inhibiting movement of the actuating rod in an opposite direction whereby the second gripping member may be moved toward the first gripping member to secure the lid'therebetween and the locking device will hold the second gripping member in position, such gripping member, in turn, holding the lid, until released. The second gripping member includes a serrated surface which is pivotably mounted on the base member in such a manner that rotation of the lid tends to rotate such surface in a direction to tighten its hold on the lid to prevent slipping thereof.

It is therefore an object of the present invention to provide a novel fixture for opening a screw-type jar.

It is a further object of the present invention to provide a fixture which is operative to tightly grip the lid of a vacuum sealed, screw-type bottle or jar to assist in the loosening and removal of such lid.

It is a still further object of the present invention to provide a jar opening fixture which securely grips the lid of the jar to prevent slipping thereof during the opening operation.

It is another object of the present invention to provide a jar opening fixture which is capable of accepting a wide range of sizes of jars and lids.

It is still another object of the present invention to provide a jar opening fixture which is adapted to be rigidly connected to a supporting surface thereby freeing both hands for the manipulation of the jar.

Still other objects, features and attendant advantages of the present invention will become apparent to those skilled in the art from a reading of the following detailed description of the preferred embodiment constructed in accordance therewith, taken in conjunction with the accompanying drawings wherein like numerals designate like parts in the several figures and wherein:

tionship to a supporting surface and a conventional vacuum sealed jar;

FIG. 2 is an enlarged sectional view of a portion of thefixture of FIG; 1 taken along the line 2-2 thereof;

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, the present fixture, generally designated 10, for use in loosening and removing a lid 7 from a screw-type jar 8, includes a generally rectangular base member 1 including an integral rim 2 entirely enclosing the edges of base member 1. Base member 1 includes holes 3 in the four corners thereof, which holes are adapted to receive conventional screws 4. Accordingly, and'as shown in FIG. 1, fixture 10 is adapted to be connected to the underneath surface of a suitable supporting member, such as a kitchen cabinet. Screws 4 extend through holes 3 in base member 1 and into supporting surface 5. In such position, rim 2, base member 1 and supporting surface 5 enclose a space 6 in which is mounted some of the operating elements of fixture 10.

Fixture includes first and second gripping members, generally designated 9 and 15, respectively, for tightly gripping opposite sides of thecircumference of lid 7. According to the preferred embodiment of the present invention, first gripping member 9 includes first and second stationary abutments 11 and 12 which are fixedly connected at one end of base member 1. 'As seen most clearly in FIGS. 3 and 4, abutments 11 and 12 may be constructed by forming. first and second U- shaped cuts in base member 1 and bending the tabs so formed away from space 6 until they extend normal to the plane of base member 1. In any event, two such abutments, l1 and 12, are provided having an acute angle therebetween so that both abutrnents 11 and 12 are adapted to be tangent to the periphery of a lid 7, as shown in FIG. 4, regardless of the size thereof.

Second gripping member 15 is mounted for linear movement relative to base member 1. More specifi-' posite end of base member 1. Gripping member 15 is adapted to move along slot 16 and includes a guide portion 17 and an operating portion 18 which are connected together via a rivet 19 As shown most clearly in FIGS. 1, 5 and 6, guide 17 is an elongated planar member, the sides of which contact base member 1 in space 6 and which has a raised portion 17 in the center thereof which extends into slot 16 to limit lateral movement of gripping member 15 as member, 15 moves along slot 16. In addition, one end of raised portion 17' of guide 17 extends downwardly, normal to the plane of guide 17, to form a connecting arm 21. Arm 21 has one end of an actuating rod 22 connected thereto by any suitable means, such as a snap .ring 23.

Referring primarily to FIGS. 1, 3 and 4, operator 18 of gripping member 15 is a generally L-shaped member having a first section 24 which is parallel to base member 1, in contact with the outer surface thereof, and which is connected to guide 17 by rivet 19. Section 24 of operator 18 has a U-shaped slot 25 at one end thereof thereby forming arms 26 and 27 which straddle arm 21 of guide 17, as shown. Accordingly, operator 18 is adapted to rotate around rivet 19, but only through a limited angle because of the stopping action of arms 23, 26 and 27. The-significance of this will become more apparent hereinafter.

Operator 18 includes a second section 28 which is made integral with section 24 and which extends normal thereto at the opposite end thereof from slot 25.

Section 28 operates in a manner similar to abutments lid 7. If desired, the surfaces of abutments 11 and 12,

facing surface 29,may also be serrated.

Referring primarily-to nos. 3 and 4, it is seen that when the longitudinal axis of operator 18 of gripping member 15 is parallel to the axis of slot 16, section 23' forms an acute angle with such axes. As operator 18 is. rotated in a clockwise direction until arm 26 contacts arm 21, the acute angle between section 28 and the axis ,of slot 16 .decreases. Conversely, as operator 18 is rotated in a counterclockwise direction until arm 27 contacts arm 21, the acute angle between section 28 and the axis of slot 16 increases. However, and as shown in FIG; 4, it is significant to note that-when operator 18 reaches the limit of its counterclockwise rotation, with arm 27 in contact with arm 21,- the angle between section28 and the axis of slot 16 is still acute and never reaches a point where section 28 is perpendicular to the axis of slot 1 6.

With a lid 7 positioned in contact with base member 1 of fixture 10, as shown in FIGS. 1 and 4, surface 29 will be in contact with the circumference of lid 7 at a point displaced from the axis of slot 16. When jar 8 is rotated to loosen lid 7, there will be a rotational force on lid 7, in the direction of arrow A, shown in FIG. 4. Such force applied to surface 29 of section 28 of operator 18 has a component perpendicular to the axis of slot 16 and tends to rotate operator 18 around rivet 19 in a clockwise direction. However, such rotation of operator 18 tends to move the area of section 28 in contact with lid 7.i n the direction of arrow B, shown in FIG. 4. As long as section 28 remains at an acute angle relative to the axis of slot 16, this movement of section 28 and surface 29, in the directionof arrow B, is such as to move section 2.8.and surface 29 towards 'abutments 11 and 12, thereby decreasing the distance between abutments 11 and12, on the one hand, and section 28 of gripping'member 15 on the other hand. As a result,

rotation of jar 8 has the automatic efiect'of tightening gripping members 9 and 15 on lid 7 so that such members increase their grip on lid 7 to prevent slipping thereof.

Gripping member 15 is manipulated into and out ofcontact with lid 7 by means of actuating rod 22.. As

discussed previously, one end of actuating rod 22 is connected to arm 21 of guide 17 of gripping member 15. The other end of actuating rod 22 may include a handle 30 which is adapted to be grasped by one hand of a user to manually move rod 22 and gripping member 15. To insure the linear motion of actuating rod 22, rod 22 extends through an opening 31 in a' flange 32 which is fixedly connected to base member 1. As shown in FIGS. 2, 3 and 4,'flange 32 may be constructed in the same manner as abutrnents 11 and 12 by forming a U-shaped cut in base member 1 and bending the tab so formed away from space 6 until it extends normal to the plane of base member 1. V

A locking device, generally designated 20, controls the manual movement of actuating rod 22 and gripping member 15. Locking device 20 is designed to permit unlimited linear movement of actuating rod 22 in a direction indicated by an arrow C a so as to bring gripping members 9 and 15 together to lock onto lid 7. Conversely, locking device 20 is designed to releasably inhibit movement of actuating rod 22 inan opposite direction, indicated by arrow D, to prevent movement of gripping member 15 away from grippingmember 9 until lid 7 has been loosened and removed from -jar 8. As shown most clearly in FIG. 2, locking device 20 is a I generally Z-shaped member having a gripping section 35, a manipulating section 36, sections 35 and 36 being parallel but spaced apart, and a connecting section.37 positioned perpendicular to sections 35 and 36 and connected between first ends of both such sections to form a unitary control element 34. Gripping section 35 has a hole 38 therein through which extends actuating rod 22. One end of hole 38 is counterbored, at 39, the counterbored end 39 of hold 38 being farthest from gripping member 15. p

Locking device 20 also includes a spring clip 40, on end of which is connected to flange 32, and which surrounds gripping section 35 of control element 34 to hold element 34 in the position shown in solid lines in FIG. 2. However, it should be noted; that manipulating section 36 may be grasped and rotated against the force of spring clip 40 to move control element 34 to the position shown in phantom in FIG. 2. v

The operation of locking device 20 may be best understood by referring to the detailed showing of FIG. 2.

under the force-of spring 45 because of the biting action of edge 42 and rod 22. It should be further noted that because of the provision of counterbore 39 at the opposite end of hole 38, there is no sharp edge on the other side of gripping section 35 which would prevent movement of actuating rod 22 in the direction of arrow C. Accordingly, actuating rod 22 is permitted unlimited linear movement in the direction of arrow C.

In operation, fixture 10 is shown in its rest position in FIG. 3, prior to use. As a practical matter, spring 45 may be adjusted to have a length to move gripping member until ,arm 21 on guide 17 of gripping member 15 contacts the end of slot 16 adjacent locking device 20. In the rest position, operator 18 of gripping member 15 may have any angular orientation. To loosen lid 7 of vacuum sealed jar 8,. jar 8 is positioned as shown in FIG. 1, with the top of lid 7 contacting base member 1 and with the circumference of lid 7 in conarrow C until surface 29 of section 28 of gripping More specifically, the junction between hole 38 and the side 41 of gripping section 35 I closest to gripping member 15 forms a sharp edge 42 which is adapted to bite into the surface of actuating rod 22 to prevent motion thereof in the direction of arrow D. However, this biting action only occurs when gripping section 35 is positioned at an acute angle relative to actuating rod 22, which is normally the case, as explained previously, and as shown in solid lines in FIG. 2. However, when manipulating section 36 is manually moved to the position shown in phantom in FIG. 2, actuating rod 22 is coaxial with the axis of hole 38 so that edge 42 cannot bite into the circumference of rod 22. In this position, rod 22 is permitted to move in the direction of arrow D.

In order to insure that gripping member 15 moves in the direction of arrow D when locking device 20 releases rod 22, a spring 45 is positioned within space 6 and connected between rim 2, adjacent flange 32, and guide 17 of gripping member 15'. Onthe other hand, when locking device 20 is in the position shown in solid lines in FIG. 2, gripping member 15 is not able to move member 15 contacts the circumference of lid 7 on the opposite side as abutrnents 11 and12. This has the effect of stretching and applying tension to spring 45. However, the effect of edge 42 of hole 38 biting into actuating rod 22 prevents rod 22 and gripping member 15 from moving away from lid 7.

As shown in FIG. 4, when surface 29 of gripping member 15 contacts the circumference of lid 7, operator 18 of gripping member 15 will be rotated until arm 27 contacts arm 21 of guide 17. The reason for this should be obvious and is due to the fact that the angular orientation of section 28 places a -torque on operator 18 to tend to rotate operator 18 until surface 29 is normal to the axis of slot 16. As explained previously, this point is never reached. 7

With lid 7 firmly gripped by gripping members 9 and 15, handle 30 of actuating rod 22 may be released and both hands may be used to grip jar 8. As a torque is applied to jar-8 in the direction of arrow A in FIG. 4, operator 18 'of gripping member 15 tends to rotate in the direction of arrow B thereby tightening the grip of members 9 and' 15 on lid 7. Accordingly, a torque may be applied to jar 8 until the yield point of lid 7 is reached whereupon lid 7 may be loosened relative to jar 8.

It can therefore be seen that in accordance with the present invention all of the problems previously discussed with respect to prior art mechanical devices are entirely eliminated by providing a novel fixture 10 which is operative to tightly grip the lid 7 of a vacuum sealed bottle or jar 8.so as to assist in the loosening and removal of lid 7. to open jar 8. In the first instance, the

design of fixture 10 is such as to apply a substantial force to lid 7 as it is attempted to be rotated to insure and slot 16. Also, fixture 10 is designed so as to be rigidly connected to a supporting surface 5, such as the bottom of a kitchen cabinet, where it will remain permane'ntly mounted. Accordingly, it is not necessary to hold fixture 10 in onehand, .whereby both hands are available for gripping jar 8.

While'the invention has been described with respect to a preferred physical embodiment constructed in accordance therewith, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the specific illustrative embodiments, but only by the scope of the appended claims.

I claim:

1. A fixture for loosening the lid of a screw-type jar comprising: 7 V

a base member;

a first gripping member fixedly mounted on said base member; i

a second gripping member mounted for linear movement relative to said base member;

a manually controllable actuating member connected to said second gripping member for move- 2 second gripping member may be moved toward said first gripping member to secure said lid therebetween and said first and second gripping members will hold said lid until said second gripping member is released by said controlling means, said second gripping member being pivotably mounted on said base member for rota tion about an axis perpendicular to the plane of said base member, said second gripping member including a surface which extends normal to said plane, said surface onsaid second gripping member always forming an acute angle with the direction of movement of said second gripping member, rotation of said lid in a direction to loosen same tending to decrease said acute angle whereby rotation of said lid tends to rotate said surface in a direction to tighten said hold on said lid.

2. A fixture according to claim 1 wherein said base member is an elongated, generally rectangular member and wherein said first gripping member is fixedly connected adjacent one end of said base member.

3. A fixture according to claim 2 wherein said base member has an elongated slot running along the longitudinal axis thereof, and wherein said second gripping member includes guide means cooperating with said slot for controlling the linear movement of said second gripping member.

4. A fixture according to claim 3 wherein said first gripping member is positioned adjacent one end of said slot.

5. A fixture according to claim 1 further comprising:

stop means for limiting rotation of said second gripping member to a range of angles in which said surface thereon alwaysforms an acute angle with said direction of movement and in which said surface always faces said first gripping member.

6. A fixture according to claim 1 wherein said surface is serrated.

A fixture according to claim 1 wherein said surface has a saw-like or toothed configuration;

8. A fixture according to claim 1 wherein said lid always contacts said surface of said second gripping member at a point displaced from the axis of said direction of movement.

9. A fixture for loosening the lid of a screw-type jar comprising: 4

a base member; a

a first gripping member fixedly mounted on said base member; I

a second gripping member mounted for linear movement relative to said base member;

a manually controllable elongated rod, one end of said rod being connected to said second gripping member for movement thereof, said rod being slideably supported for linear movement on said base member; and

means for controlling the movement of said actuating member, said controlling means permitting unlimited linear movement of said actuating member in a direction to bring said first and second grippingmembers together, said controlling means releasably inhibiting movement of said actuating member in an opposite direction whereby said second gripping member'may be moved towards said first gripping member to secure said lid therebetween and said first andsecond gripping members will hold said lid until said second gripping member is released by said controlling means, said controlling means comprising:

a pivotable control element having a hole therethrough, said rod extending through said hole; and

means biasing said control element in a position with the axis of said hole displaced from the axis of said rod, the edge of said hole closest said one end of said rod biting into the surface of said ro'd v to prevent motion thereof in said opposite direction.

10. A fixture according to claim 9 wherein said control element is adapted to be manually pivoted against the force of said biasing means to align said axis of said hole with said axis of said rod to disengage said edge of said hole and said rod to release said rod and to permit movement thereof in said opposite direction.

11. A fixture according to claim 10 further comprismg: I 1

spring means for automatically moving said second gripping means and said rod in said opposite direction when released.

12. A fixture according to claim 9 wherein the end of said hole farthest from said one end of said rod is counterbored to eliminate any sharp edge and to permit unlimited movement of said rod in said direction to bring said gripping members together.

i i i 

1. A fixture for loosening the lid of a screw-type jar comprising: a base member; a first gripping member fixedly mounted on said base member; a second gripping member mounted for linear movement relative to said base member; a manually controllable actuating member connected to said second gripping member for movement thereof; and means for controlling the movement of said actuating member, said controlling means permitting unlimited linear movement of said actuating member in a direction to bring said first and second gripping members together, said controlling means releasably inhibiting movement of said actuating member in an opposite direction whereby said second gripping member may be moved toward said first gripping member to secure said lid therebetween and said first and second gripping members will hold said lid until said second gripping member is released by said controlling means, said second gripping member being pivotably mounted on said base member for rotation about an axis perpendicular to the plane of said base member, said second gripping member including a surface which extends normal to said plane, said surface on said second gripping member always forming an acute angle with the direction of movement of said second gripping member, rotation of said lid in a direction to loosen same tending to decrease said acute angle whereby rotation of said lid tends to rotate said surface in a direction to tighten said hold on said lid.
 2. A fixture according to claim 1 wherein said base member is an elongated, generally rectangular member and wherein said first gripping member is fixedly connected adjAcent one end of said base member.
 3. A fixture according to claim 2 wherein said base member has an elongated slot running along the longitudinal axis thereof, and wherein said second gripping member includes guide means cooperating with said slot for controlling the linear movement of said second gripping member.
 4. A fixture according to claim 3 wherein said first gripping member is positioned adjacent one end of said slot.
 5. A fixture according to claim 1 further comprising: stop means for limiting rotation of said second gripping member to a range of angles in which said surface thereon always forms an acute angle with said direction of movement and in which said surface always faces said first gripping member.
 6. A fixture according to claim 1 wherein said surface is serrated.
 7. A fixture according to claim 1 wherein said surface has a saw-like or toothed configuration.
 8. A fixture according to claim 1 wherein said lid always contacts said surface of said second gripping member at a point displaced from the axis of said direction of movement.
 9. A fixture for loosening the lid of a screw-type jar comprising: a base member; a first gripping member fixedly mounted on said base member; a second gripping member mounted for linear movement relative to said base member; a manually controllable elongated rod, one end of said rod being connected to said second gripping member for movement thereof, said rod being slideably supported for linear movement on said base member; and means for controlling the movement of said actuating member, said controlling means permitting unlimited linear movement of said actuating member in a direction to bring said first and second gripping members together, said controlling means releasably inhibiting movement of said actuating member in an opposite direction whereby said second gripping member may be moved towards said first gripping member to secure said lid therebetween and said first and second gripping members will hold said lid until said second gripping member is released by said controlling means, said controlling means comprising: a pivotable control element having a hole therethrough, said rod extending through said hole; and means biasing said control element in a position with the axis of said hole displaced from the axis of said rod, the edge of said hole closest said one end of said rod biting into the surface of said rod to prevent motion thereof in said opposite direction.
 10. A fixture according to claim 9 wherein said control element is adapted to be manually pivoted against the force of said biasing means to align said axis of said hole with said axis of said rod to disengage said edge of said hole and said rod to release said rod and to permit movement thereof in said opposite direction.
 11. A fixture according to claim 10 further comprising: spring means for automatically moving said second gripping means and said rod in said opposite direction when released.
 12. A fixture according to claim 9 wherein the end of said hole farthest from said one end of said rod is counterbored to eliminate any sharp edge and to permit unlimited movement of said rod in said direction to bring said gripping members together. 